A traditional metallic waveguide feed 15 for a reflector antenna 10 is illustrated in FIG. 1 and represents the current art in reflector systems for portable communications. Reflector antenna technology is one of the most cost effective and architecturally simple ways to realize high gain, narrow beam width radiation patterns since the electrically large reflector surface 12 is spatially excited from a propagating electromagnetic wave 14 originating from feed antenna 15. An electrically small feed 15 therefore effectively excites an electrically large reflecting surface 12.
A constrained feed phased array antenna, in contrast, is drastically more complex and expensive than reflector technology for the same electrical size due to the large number of interconnects required. Phase scanned lens antenna are also possible, and are less complex and costly than constrained feed phased arrays, however, they also require a large number of radiating elements and RF (radio frequency) interconnects to realize high gain and narrow beam radiation patterns.
Certain systems, such as landing and imaging radars, only need to electronically scan a narrow antenna beam over limited angular sectors. A limited scan reflector system can be appropriate for such applications. The limited scan, electronically scanned reflector utilizes electrically smaller phased array antenna feeds to generate a variable phase excitation to the reflector assembly. This allows limited range beam steering off the reflector's normal axis. The limited scanned reflector utilizes traditional phase shifter based phased array technology, such as microstrip antenna technology.
While all of these antenna systems describe above are useful and work well for their designed applications, all of these antenna technology types have a plurality of limitations, particularly at millimeter (mm) and microwave frequencies.
Therefore, it would be desirable to provide reflector antenna technology that incorporates the benefits of the other antenna systems to provide a low cost antenna that works well at the mm and microwave frequencies.